Pneumatically operated averaging relay construction and system utilizing the same

ABSTRACT

A housing means carrying a plurality of diaphragm members disposed in stacked relation and cooperating with the housing means to define a plurality of chambers disposed in stacked relation and separated from each other by the diaphragm members. Each diaphragm member has a central post means and a plurality of integral diaphragm portions axially spaced on the post means and extending radially outwardly therefrom in substantially parallel spaced relation to each other. Interconnecting means interconnect the post means of the diaphragm members together whereby the diaphragm members are adapted to move in unison in the housing means.

United States Patent Kreuter et a1.

[451 May9, 1972 [54] PNEUMATICALLY OPERATED AVERAGING RELAY CONSTRUCTIONAND SYSTEM UTILIZING THE SAME [72] Inventors: Kenneth G. Kreuter; WalterJ. Berleyoung, both of Goshen, lnd.

[73 Assignee: Robertshaw Controls Company,

Richmond, Va.

[22] Filed: Aug. 13, 1970 [21] Appl. No.: 63,475

521 U.S. C1 .L ..137/85, 137/86 [51] Int. Cl. .FlSb 5/00, 605d 16/00[58] Field of Search ..137/82, 85, 86; 92/49 [56] References CitedUNITED STATES PATENTS 3,461,896 8/1969 Holloway ..l37/85X Kreuter..137/82 X Smith 137/85 Primary Examiner-Alan Cohan Attorney-candor,Candor & Tassone, Auzville Jackson, Jr. and Robert L. Marben [57]ABSTRACT A housing means carrying a plurality of diaphragm membersdisposed in stacked relation and cooperating with the housing means todefine a plurality of chambers disposed in stacked relation andseparated from each other by the diaphragm members. Each diaphragmmember has a central post means and a plurality of integral diaphragmportions axially spaced on the post means and extending radiallyoutwardly therefrom in substantially parallel spaced relation to eachother. Interconnecting means interconnect the post means of thediaphragm members together whereby the diaphragm members are adapted tomove in unison in the housing means.

16 Claims, 3 Drawing Figures u 39 3O 4 45A 8 31 46A wi'g 5?: 27 56 34 58l4 PATENTEDMAY 9 I972 SHEET 1 OF 2 IFIG.2

INVENTORS KENNETH G. KREUTER WALTER J. BERLEYOU THEIR ATTORNEYSPATENTEDMAY 9 I972 3,661,164

snmz 0F 2 XNVENTORS KENNETH G.KREUTER 8: WALTER J. BERLEYOUNGd'vbydoulni'zawm THEIR ATTORNEYS PNEUMATICALLY OPERATED AVERAGING RELAYCONSTRUCTION AND SYSTEM UTILIZING THE SAME This invention relates to anaveraging relay construction and to a pneumatic control system utilizingsuch averaging relay construction.

It is well known that pneumatically operated averaging relayconstructions have been provided wherein the relay construction willtransmit a control pneumatic signal from a pneumatic source in relationto the average or sum of a plurality of pneumatic signals directed tothe relay construction.

Accordingly, it is a feature of the invention to provide such anaveraging relay construction having improved parts which facilitate theaccuracy of operation thereof as well as facilitate the fabricationthereof whereby the relay construction can be relatively compact andeconomical.

In particular, one embodiment of this invention comprises a housingmeans. A plurality of diaphragm members are disposed in the housingmeans in stacked relation and cooperate therewith to define a pluralityof chambers disposed in stacked relation and separated from each otherby the diaphragm members. Each diaphragm member has a central post meansand a plurality of integral diaphragm portions axially spaced on thepost means and extending radially outwardly therefrom in substantiallyparallel spaced relation to each other. The diaphragm members aresubstantially identical to each other. Interconnecting meansinterconnect the post means of the diaphragm members together wherebythe diaphragm members are adapted to move in unison relative to thehousing means to produce a control signal from a pneumatic source inrelation to the average of a plurality of pneumatic signals directed tothe relay construction.

Accordingly, it is an object of this invention to provide an improvedaveraging relay construction having one or more of the novel featuresset forth above or hereinafter shown or described.

Another object of this invention is to provide a pneumatic controlsystem utilizing such a relay construction or the like.

Other objects, uses and advantages of this invention are apparent from areading of this description which proceeds with reference to theaccompanying drawings forming a part thereof and wherein:

FIG. 1 is a top perspective view of the improved averaging relayconstruction of this invention.

FIG. 2 is an enlarged cross-sectional view taken substantially on line2-2 of FIG. 1.

FIG. 3 is an exploded perspective view illustrating the various parts ofthe relay construction of FIGS. 1 and 2.

While the various features of this invention are hereinafter describedand illustrated as being particularly adapted to provide an averagingrelay construction to be utilized with a pressure operated pneumaticcontrol system, it is to be understood that the various features of thisinvention can be utilized singly or in any combination thereof toprovide a relay construction for other types of pneumatic controlsystems as desired.

Therefore, this invention is not to be limited to only the embodimentsillustrated in the drawings, because the drawings are merely utilized toillustrate one of the wide variety of uses of this invention.

Referring now to FIGS. l-3, the improved relay construction of thisinvention is generally indicated by the reference numeral and is adaptedto be utilized in a pneumatic control system generally indicated by thereference numeral 11 in FIG. 2, the control system 11 comprising apneumatic fluid pressure source 12 interconnected by suitable conduitmeans 13 to a nipple connection 14 of a housing means 15 of the relayconstruction 10, a pneumatically operated controlled device 16interconnected by suitable conduit means 17 to another nipple means 18of the relay construction 10 and a pair of pneumatically operatedpneumatic signal sending means 19 and 20 respectively interconnected bysuitable conduit means 2l and 22 to nipple means 23 and 24 of the relayconstruction 10. For example, the pneumatic control system II cancomprise a heat exchanging system wherein the controlled device 16comprises a pneumatically operated heat exchanger means and thepneumatic signal sending means 19 and 20 can respectively comprise atemperature sensing means and a set point adjusting means so that theheat exchanger means 16 will be operated in relation to the average ofthe signals produced by the devices 19 and 20 in a manner well known inthe art.

The housing means 15 of the relay construction 10 includes a cup-shapedhousing member 25 having a closed end wall means 26 and an opened end 27receiving four other housing members 28, 29, 30 and 31 therein instacked relation with the outboard housing member 31 having an outwardlydirected substantially annular tongue or rib means 32 snap-fittinglyreceived in an annular groove or recess 33 in the interior side wallmeans 34 of the cup-shaped housing member 25 in the manner illustratedin FIG. 2 to not only secure the-housing members 25 and 28-31 together,but also to secure and seal the same to two diaphragm members 35 and 35Acooperating with the housing means 15 to define five chambers 36, 37,38, 39 and 40 disposed in stacked relation in the housing means 15 andseparated from each other by diaphragm portions 41, 42, and 41A, 42A ofthe diaphragm members 35 and 35A.

The diaphragm portions 41, 42 and 41A, 42A of the diaphragm members 35and 35A are formed integrally with axially extending post means 43 and43A of the diaphragm members 35 and 35A and are formed of flexiblematerial, such as rubber or the like, and by molding or the like. Thediaphragm portions 41, 42 and 41A, 42A have outer annular bead means 44and 45, 44A and 45A at the outer peripheries thereof to be respectivelyreceived and sealed in annular groove means defined between thecooperating surfaces of the housing members 26 and 28-31 are illustratedwhereby the diaphragm members 35 and 35A are adapted to be secured inthe stacked, sealed relation as illustrated in FIG. 2. Since thediaphragm portions 42 and 42A are substantially larger in radial extentand thickness than the radial extent and thickness of the diaphragmportions 41 and 41A, the larger diaphragm portions 42 and 42A can besuitably reinforced by reinforcing plate means 46 and 46A formedseparate from and secured to the reinforcing means 47 and 47Arespectively of the post means 43 and 43A in any suitable manner.

The reinforcing means 47 and 47A of the post means 43 and 43A of thediaphragm members 35 and 35A are respectively provided with internalthreaded bore means 48 and 48A which receive externally threadedfastening means 49 to secure the post means 43 and 43A of the diaphragmmembers 35 and 35A together so that the diaphragm members 35 and 35Awill move in unison relative to the housing means 15 in a mannerhereinafter described.

The reinforcing means 47A of the post means 43A of the diaphragm member35A has a portion thereof 50 extending between the post means 43A and 43of the diaphragm members 35 and 35A to space the same from each otherand provide fluid interconnection means to the chamber 38. Also, thepost means 43 and 43A of the diaphragm members 35 and 35A havetransverse passage means 51 and 51A provided therein so as to berespectively disposed in fluid communication with each other at thespacing between the post means 43 and 43A as well as in fluidcommunication with the outboard chambers 40 and 36 as illustrated andfor a purpose hereinafter described, the chamber 36 being partly definedby an outwardly directed cup-shaped portion 52 of the end wall means 26of the housing member 25 to permit axial movement of the diaphragmmembers 35 and 35A as will be apparent hereinafter.

The housing member 31 has an inwardly directed valve seat projection 53provided with a passage 54 passing therethrough and being adapted tointerconnect the chamber 40 with the exterior of the housing means 15.However, an outwardly directed resilient projection 55 on the diaphragmportion 42A of the diaphragm member 35A is adapted to control theopening and closing of the valve seat means 53 as will be apparenthereinafter. Since the passage means 51 and 51A of the diaphragm members35 and 35A are offset relative to the valve seat 53, the chambers 40, 36and 38 are always fluidly interconnected together regardless of theposition of the diaphragm members 35 and 35A relative to the housingmeans 15.

The nipple projections 14 and 18 of the housing member 31 has suitablepassage means 56 and 57 passing respectively therethrough andrespectively interconnecting the pneumatic source 12 and control device16 to the chamber 40 of the relay construction 10. If desired, thepassage means 56 and 57 of the nipple extensions 14 and 18 can beprovided with suitable filtering material 58 to filter the fluid flowtherethrough. In addition, the passage means 56 of the nipple means 14can have suitable restriction means 59 therein that is formed integrallywith the housing member 31.

The nipple extension 23 and 24 of the housing members 28 and 30 areadapted to respectively project out through opening means 60 and 61 ofthe housing members 25 and 31 and have suitable passage means 62 and 63passing therethrough to respectively fluidly interconnect the pneumaticsignal sending means 19 and 20 to the chambers 37 and 39 of the relayconstruction 10.

Since the passage means 51 and 51A of the diaphragm members 35 and 35Aare disposed in offset relation to the passage 54 in the valve seatmeans 53, the chamber 40 of the relay construction is always in fluidcommunication with the chamber 38 and chamber 36 so that the pressureper square inch acting downwardly on the diaphragm portions 41A and 41of the diaphragm members 35 and 35A is exactly equal to the pressure persquare inch in the chamber 40.

From the above description of the relay construction 10, it can be seenthat the various parts of the relay construction 10 of this inventioncan be formed from molded plastic material to be assembled together in asimple and economical manner whereby the only means for securing thehousing members 26 and 28-31 and diaphragm members 35 and 35A togetheris provided by the snap-fit relation between the cup-shaped housingmember 25 and the outboard housing member 31 while the only fasteningmeans provided between the diaphragm members 35 and 35A is the threadedfastening member 39.

The operation of the relay construction 10 and the pneumatic controlsystem 11 will now be described.

Since the effective areas of the diaphragm members 35 and 35A aredesigned such that the sum of the input signal pressures directed to thechambers 37 and 39 oppose the forces of the output pressure actingagainst equal effective areas on the under sides of the diaphragmportions 42 and 42A of the diaphragm members 35 and 35A, balancingforces are provided which positions the diaphragm members 35 and 35A tocontrol the rate of exhaust from the chamber 40 to the atmospherethrough the valve seat means 53 so as to determine the output pressurebeing directed to the control device 16.

Thus, when the pneumatic signals being directed from the pneumaticsignal sending means 19 and are at 0 psi, the diaphragm members 35 and35A are forced upwardly in FIG. 2 by the pressure of the fluid from thesource 12 entering the chamber 40 through the restrictor 59 and actingagainst the undersides of the diaphragm portions 42 and 42A at the charmbers 38 and 40 whereby the fluid in the chambers 40, 38 and 36 exhauststhrough the opened passage means 54 of the valve seat means 53 so thatthe output pressure to the control device 16 is at 0 psi. However, whenthe pressures of the signals from the signal sending devices 19 and 20increases, the same act on the uppersides of the diaphragm portions 42and 42A at the chambers 37 and 39 to force the diaphragm members 35 and35A downwardly to reduce the rate of exhaust of the air from the chamber40 through the valve seat means 53 so that the output pressure to thecontrol device 16 correspondingly increases.

in this manner. as the sum of the pressures of the pneumatic signalsfrom the signal sending devices 19 and 20 decreases, the pressure to thecontrol device 16 correspondingly decreases and when the sum of thesignals from the devices 19 and 20 increases, the force of the pressurefluid to the control device 16 correspondingly increases.

Thus, it can be seen that this invention not only provides an improvedpneumatically operated averaging relay construction, but also thisinvention provides an improved fluid system utilizing such a relayconstruction.

While the form of the invention now preferred has been disclosed asrequired by the patent statutes, other forms may be utilized, all comingwithin the scope of the claims which follow.

What is claimed is:

1. An averaging relay construction comprising a housing means, aplurality of diaphragm members disposed in said housing means in stackedrelation and cooperating therewith to define a plurality of chambersdisposed in stacked relation and separated from each other by saiddiaphragm members, each diaphragm member having a central post means anda plurality of integral diaphragm portions axially spaced on said postmeans and extending radially outwardly therefrom in substantiallyparallel spaced relation to each other, and means interconnecting saidpost means of said diaphragm members together whereby said diaphragmmembers are adapted to move in unison in said housing means, said postmeans of said diaphragm members having interconnecting passagestherethrough for fluidly interconnecting together the outboard chambersof the stack thereof, said post means of said diaphragm members beinginterconnected together by said means to define space means therebetweenthat fluidly interconnects said outboard chambers by way of saidinterconnecting passages to an intermediate chamber of said stackthereof.

2. An averaging relay construction as set forth in claim 1 wherein saiddiaphragm members are substantially identical in construction.

3. An averaging relay construction as set forth in claim 1 wherein eachdiaphragm member has one diaphragm portion that is relatively large inradial extent and another diaphragm portion that is relatively small inradial extent.

4. An averaging relay construction as set forth in claim 3 wherein eachdiaphragm member has reinforcing means in said one relatively largediaphragm portion thereof.

5. An averaging relay construction as set forth in claim 1 wherein eachdiaphragm member has reinforcing means in said post means thereof.

6. An averaging relay construction comprising a housing means, aplurality of diaphragm members disposed in said housing means in stackedrelation and cooperating therewith to define a plurality of chambersdisposed in stacked relation and separated from each other by saiddiaphragm members, each diaphragm member having a central post means anda plurality of integral diaphragm portions axially spaced on said postmeans and extending radially outwardly therefrom in substantiallyparallel spaced relation to each other, and means interconnecting saidpost means of said diaphragm members together whereby said diaphragmmembers are adapted to move in unison in said housing means, eachdiaphragm member having reinforcing means in said post means thereof,said reinforcing means of said post means of each diaphragm memberhaving a threaded bore, said means interconnecting said post means ofsaid diaphragm members together comprising threaded fastening meansthreadedly disposed in said threaded bores of said post means.

7. An averaging relay construction as set forth in claim 1 wherein saidhousing means comprises a plurality of housing members, one of saidhousing members being cup-shaped and having an open end and a closedend, the other of said housing members being disposed in said open endof said cup-shaped housing member in stacked relation.

8. An averaging relay construction as set forth in claim 7 wherein saidone housing member and the outboard housing member of the other housingmembers are snap-fitted together to secure said housing members anddiaphragm members together.

9. in a pneumatic control system having a source of pneumatic fluid, apneumatically operated device, and pneumatic signal sending means, theimprovement comprising an averaging relay construction comprising ahousing means, a plurality of diaphragm members disposed in said housingmeans in stacked relation and cooperating therewith to define aplurality of chambers disposed in stacked relation and separated fromeach other by said diaphragm members, each diaphragm member having acentral post means and a plurality of integral diaphragm portionsaxially spaced on said post means and extending radially outwardlytherefrom in substantially parallel spaced relation to each other, meansinterconnecting said post means of said diaphragm members togetherwhereby said diaphragm members are adapted to move in unison in saidhousing means, means interconnecting said pneumatic source and saidpneumatically operated device to one of said chambers, said housingmeans having an exhaust port leading to said one chamber and beingcontrolled by one of said diaphragm members, and means interconnectingsaid signal sending means to other of said chambers, said post means ofsaid diaphragm members having interconnecting passages therethrough forfluidly interconnecting together the outboard chambers of the stackthereof, said one chamber being one of said outboard chambers, said postmeans of said diaphragm members being interconnected together by saidmeans to define space means therebetween that fluidly interconnects saidoutboard chambers by way of said interconnecting passages to anintermediate chamber of said stack thereof.

[0. ln a pneumatic control system as set forth in claim 9, the furtherimprovement wherein said diaphragm members are substantially identicalin construction.

11. In a pneumatic control system as set forth in claim 9, the furtherimprovement wherein each diaphragm member has one diaphragm portion thatis relatively large in radial extent and another diaphragm portion thatis relatively small in radial extent.

12. In a pneumatic control system as set forth in claim 11, the furtherimprovement wherein each diaphragm member has reinforcing means in saidone relatively large diaphragm portion thereof.

13. In a pneumatic control system as set forth in claim 9, the furtherimprovement whereineach diaphragm member has reinforcing means in saidpost means thereof.

14. In a pneumatic control system as set forth in claim 9, the furtherimprovement wherein said housing means comprises a plurality of housingmembers, one of said housing members being cup-shaped and having an openend and a closed end, the other of said housing members being disposedin said open end of said cup-shaped housing member in stacked relation.

15. In a pneumatic control system as set forth in claim 14, the furtherimprovement wherein said one housing member and the outboard housingmember of the other housing members are snap-fitted together to securesaid housing members and diaphragm members together.

16. In a pneumatic control system having a source of pneumatic fluid, apneumatically operated device, and pneumatic signal sending means, theimprovement comprising an averaging relay construction comprising ahousing means, a plurality of diaphragm members disposed in said housingmeans in stacked relation and cooperating therewith to define aplurality of chambers disposed in stacked relation and separated fromeach other by said diaphragm members, each diaphragm member having acentral post means and a plurality of integral diaphragm portionsaxially spaced on said post means and extending radially outwardlytherefrom in substantially parallel spaced relation to each other, meansinterconnecting said post means of said diaphragm members togetherwhereby said diaphragm members are adapted to move in unison in saidhousing means, means interconnecting said pneumatic source and saidpneumatically operated device to one of said chambers, said housingmeans having an exhaust port leading to said one chamber and beingcontrolled by one of said diaphragm members, and means interconnectingsaid signal sending means to other of said chambers, eac diaphragmmember having reinforcing means in said post means thereof, saidreinforcing means of said post means of each diaphragm member having athreaded bore, said means interconnecting said post means of saiddiaphragm members together comprising threaded fastening meansthreadedly disposed in said threaded bores of said post means.

1. An averaging relay construction comprising a housing means, aplurality of diaphragm members disposed in said housing means in stackedrelation and cooperating therewith to define a plurality of chambersdisposed in stacked relation and separated from each other by saiddiaphragm members, each diaphragm member having a central post means anda plurality of integral diaphragm portions axially spaced on said postmeans and extending radially outwardly therefrom in substantiallyparallel spaced relation to each other, and means interconnecting saidpost means of said diaphragm members together whereby said diaphragmmembers are adapted to move in unison in said housing means, said postmeans of said diaphragm members having interconnecting passagestherethrough for fluidly interconnecting together the outboard chambersof the stack thereof, said post means of said diaphragm members beinginterconnected together by said means to define space means therebetweenthat fluidly interconnects said outboard chambers by way of saidinterconnecting passages to an intermediate chamber of said stackthereof.
 2. An averaging relay construction as set forth in claim 1wherein said diaphragm members are substantially identical inconstruction.
 3. An averaging relay construction as set forth in claim 1wherein each diaphragm member has one diaphragm portion that isrelatively large in radial extent and another diaphragm portion that isrelatively small in radial extent.
 4. An averaging relay construction asset forth in claim 3 wherein each diaphragm member has reinforcing meansin said one relatively large diaphragm portion thereof.
 5. An averagingrelay construction as set forth in claim 1 wherein each diaphragm memberhas reinforcing means in said post means thereof.
 6. An averaging relayconstruction Comprising a housing means, a plurality of diaphragmmembers disposed in said housing means in stacked relation andcooperating therewith to define a plurality of chambers disposed instacked relation and separated from each other by said diaphragmmembers, each diaphragm member having a central post means and aplurality of integral diaphragm portions axially spaced on said postmeans and extending radially outwardly therefrom in substantiallyparallel spaced relation to each other, and means interconnecting saidpost means of said diaphragm members together whereby said diaphragmmembers are adapted to move in unison in said housing means, eachdiaphragm member having reinforcing means in said post means thereof,said reinforcing means of said post means of each diaphragm memberhaving a threaded bore, said means interconnecting said post means ofsaid diaphragm members together comprising threaded fastening meansthreadedly disposed in said threaded bores of said post means.
 7. Anaveraging relay construction as set forth in claim 1 wherein saidhousing means comprises a plurality of housing members, one of saidhousing members being cup-shaped and having an open end and a closedend, the other of said housing members being disposed in said open endof said cup-shaped housing member in stacked relation.
 8. An averagingrelay construction as set forth in claim 7 wherein said one housingmember and the outboard housing member of the other housing members aresnap-fitted together to secure said housing members and diaphragmmembers together.
 9. In a pneumatic control system having a source ofpneumatic fluid, a pneumatically operated device, and pneumatic signalsending means, the improvement comprising an averaging relayconstruction comprising a housing means, a plurality of diaphragmmembers disposed in said housing means in stacked relation andcooperating therewith to define a plurality of chambers disposed instacked relation and separated from each other by said diaphragmmembers, each diaphragm member having a central post means and aplurality of integral diaphragm portions axially spaced on said postmeans and extending radially outwardly therefrom in substantiallyparallel spaced relation to each other, means interconnecting said postmeans of said diaphragm members together whereby said diaphragm membersare adapted to move in unison in said housing means, meansinterconnecting said pneumatic source and said pneumatically operateddevice to one of said chambers, said housing means having an exhaustport leading to said one chamber and being controlled by one of saiddiaphragm members, and means interconnecting said signal sending meansto other of said chambers, said post means of said diaphragm membershaving interconnecting passages therethrough for fluidly interconnectingtogether the outboard chambers of the stack thereof, said one chamberbeing one of said outboard chambers, said post means of said diaphragmmembers being interconnected together by said means to define spacemeans therebetween that fluidly interconnects said outboard chambers byway of said interconnecting passages to an intermediate chamber of saidstack thereof.
 10. In a pneumatic control system as set forth in claim9, the further improvement wherein said diaphragm members aresubstantially identical in construction.
 11. In a pneumatic controlsystem as set forth in claim 9, the further improvement wherein eachdiaphragm member has one diaphragm portion that is relatively large inradial extent and another diaphragm portion that is relatively small inradial extent.
 12. In a pneumatic control system as set forth in claim11, the further improvement wherein each diaphragm member hasreinforcing means in said one relatively large diaphragm portionthereof.
 13. In a pneumatic control system as set forth in claim 9, thefurther improvement wherein each diaphragm member has reinforcing meansin said post means thereof.
 14. In a pneumatic control system as setforTh in claim 9, the further improvement wherein said housing meanscomprises a plurality of housing members, one of said housing membersbeing cup-shaped and having an open end and a closed end, the other ofsaid housing members being disposed in said open end of said cup-shapedhousing member in stacked relation.
 15. In a pneumatic control system asset forth in claim 14, the further improvement wherein said one housingmember and the outboard housing member of the other housing members aresnap-fitted together to secure said housing members and diaphragmmembers together.
 16. In a pneumatic control system having a source ofpneumatic fluid, a pneumatically operated device, and pneumatic signalsending means, the improvement comprising an averaging relayconstruction comprising a housing means, a plurality of diaphragmmembers disposed in said housing means in stacked relation andcooperating therewith to define a plurality of chambers disposed instacked relation and separated from each other by said diaphragmmembers, each diaphragm member having a central post means and aplurality of integral diaphragm portions axially spaced on said postmeans and extending radially outwardly therefrom in substantiallyparallel spaced relation to each other, means interconnecting said postmeans of said diaphragm members together whereby said diaphragm membersare adapted to move in unison in said housing means, meansinterconnecting said pneumatic source and said pneumatically operateddevice to one of said chambers, said housing means having an exhaustport leading to said one chamber and being controlled by one of saiddiaphragm members, and means interconnecting said signal sending meansto other of said chambers, each diaphragm member having reinforcingmeans in said post means thereof, said reinforcing means of said postmeans of each diaphragm member having a threaded bore, said meansinterconnecting said post means of said diaphragm members togethercomprising threaded fastening means threadedly disposed in said threadedbores of said post means.